ocache

type LoadFunc func(ctx context.Context, id string) (value Object, err error)

type OCache interface {
	// DoLockedIfNotExists does an action if the object with id is not in cache
	// under a global lock, this will prevent a race which otherwise occurs
	// when object is created in parallel with action
	DoLockedIfNotExists(id string, action func() error) error
	// Get gets an object from cache or create a new one via 'loadFunc'
	// Increases the object refs counter on successful
	// When 'loadFunc' returns a non-nil error, an object will not be stored to cache
	Get(ctx context.Context, id string) (value Object, err error)
	// Pick returns value if it's presents in cache (will not call loadFunc)
	Pick(ctx context.Context, id string) (value Object, err error)
	// Add adds new object to cache
	// Returns error when object exists
	Add(id string, value Object) (err error)
	// Remove closes and removes object
	Remove(ctx context.Context, id string) (ok bool, err error)
	// ForEach iterates over all loaded objects, breaks when callback returns false
	ForEach(f func(v Object) (isContinue bool))
	// GC frees not used and expired objects
	// Will automatically called every 'gcPeriod'
	GC()
	// Len returns current cache size
	Len() int
	// Close closes all objects and cache
	Close() (err error)
}

type Object interface {
	Close() (err error)
	TryClose(objectTTL time.Duration) (res bool, err error)
}

type Option func(*oCache)